#include<iostream>
#include<iomanip>
#include<cmath>
using namespace std;
const int N = 1e5 + 10;
int arr[N];
int n, k;
int main()
{
	cin >> n >> k;
	int ans = 0;
	for (int i = 0; i < n; i++) {
		cin >> arr[i];
		ans += arr[i];
	}
	double res = ans * 1.0 / n;
	//	int t=res; 
	//	cout<<t<<".";
	//	double res2=(double)res-t; 
		//0.3434234242
	int cnt = 0;
	int t = (int)res;
	while (t) {
		cnt++;
		t /= 10;
	}
	int a = ans;
	a *= 10;
	int b = n;
	bool flag = 0;
	for (int i = 1; i <= k; i++) {
		if (!flag) {
			int k1 = (a - a % b) / b;
			int t1 = k1 % 10;
			int a1 = k1;
			int cnt = 0;
			while (a1) {
				cnt++;
				a1 /= 10;
			}
			cout << k1 / 10;
			cout << ".";
			cout << t1;
			flag = 1;
		}
		else {
			cout << (a - a % b) / b;
		}
		a = (a % b) * 10;
	}
	return 0;
}